1. Field of the Invention
The present invention relates to shutoff systems for steam cleaners and more particularly pertains to a new safety shutoff system for steam cleaners and combination steam and water cleaners for permitting safe shutoff at the hand held spray gun of the steam or combination cleaner.
2. Description of the Prior Art
Known prior art systems pertaining to pressurized cleaners include U.S. Pat. No. 5,259,556; U.S. Pat. No. 4,368,757; U.S. Pat. No. 4,217,924; U.S. Pat. No. 3,814,321; U.S. Pat. No. 4,321,219; U.S. Pat. No. 3,595,268; U. S. Pat. No. 3,669,297; U.S. Pat. No. 4,738,541; U.S. Pat. No. 3,773,065; U.S. Pat. No. 5,678,593; U.S. Pat. No. 3,490,482; U.S. Pat. No. 3,355,324; PCT Patent No. WO 93/04623 (Inventor: Held); PCT Patent No. WO 94/24920 (Inventor: Sham); and U.S. Pat. No. Des. 287,653.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new safety shutoff system for steam cleaners and combination steam and water cleaners. Safety concerns require that pressurized fluid cleaning devices have a means for stopping fluid flow from the outlet of the cleaning device that is located at (or very near) the pressurized fluid outlet (which is typically remote from the main body of the steam cleaning device). The use of shutoff systems located proximate to the fluid outlet of heated water cleaners is known in the prior art. However, using only a conventional shutoff valve found on a conventional heated water cleaning device has been avoided on a steam cleaning device because of significant safety concerns. Simply blocking steam flow at the outlet of the steam cleaning device, as is done in conventional heated water cleaning devices can cause a build up of internal water and steam temperatures and pressures in the steam cleaning device greatly increases the risk of an explosion of the steam cleaning device from the build up.
A safety system that immediately shuts off the fluid heater is also undesirable because this interruption can cause a user to have to wait for a period of time after the interruption before sufficient amounts of steam and heated water are available again at the fluid outlet.
Because of the inherent dangers and drawbacks of employing a shutoff valve at the fluid outlet of a steam cleaning device, known steam cleaning devices have only employed shutoffs at the main body of the steam cleaning device that shut off the pressuring pump and the fluid heater. The danger of having a shutoff remote from the fluid outlet has been considered lesser than the explosion hazard.
In these respects, the safety shutoff system for steam cleaners and combination steam and water cleaners according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of permitting safe shutoff at the hand held spray gun of the steam or combination cleaner.